I have a double wall waterer. It has a five gallon capacity. When more than one gallon of water is in it seems as though the trough over-fills and water comes over the side. The spring and gasket seem to work fine in that no water comes out until the top is put on. If I only put in one gallon of water the problem doesn't exists. This thing is less than six months old. Has anyone experienced this problem and know of a solution? thanks in advance.